ADENOENDOCRINE CELL-CARCINOMA OF THE GALLBLADDER - A HISTOCHEMICAL AND IMMUNOHISTOCHEMICAL STUDY

A case of adenoendocrine cell carcinoma of the gallbladder with adenom ucous cells and neuroendocrine cells is reported. A histochemical and immunohistochemical study revealed that the primary tumor in the gallb ladder was composed of mucus-secreting and/or argyrophil cells. Furthe rmore, the tumor showed a positive reaction to carcinoembryonic antige n (CEA) in all tumor cells, to chromogranin A and cytokeratin in many tumor cells, to endocrine granule constituent (EGC) in some tumor cell s, and to serotonin and somatostatin in a few tumor cells. In addition , a few mucous cells showed argyrophilia and EGC-positivity in their c ytoplasms. This case suggests that the adenoendocrine cell tumor is de rived from endodermal stem cells as a result of bidirectional (exocrin e and endocrine) differentiation.